SparkFun
SparkFun Mini Spectral UV Sensor - AS7331 (Qwiic)
· MPN: SEN-23518
The SparkFun Mini Spectral UV Sensor features the AS7331 from ams OSRAM, measuring ultraviolet radiation across three dedicated channels: UVA (320–400 nm), U...
The SparkFun Mini Spectral UV Sensor features the AS7331 from ams OSRAM, measuring ultraviolet radiation across three dedicated channels: UVA (320–400 nm), UVB (280–320 nm), and UVC (200–280 nm). Each channel has its own photodiode with built-in interference filter for high sensitivity and accuracy.
This Qwiic Mini breakout (1 × 0.5 in.) communicates over I²C and includes two Qwiic connectors for solderless daisy-chaining, plus a 0.1"-spaced through-hole header with Interrupt and Sync pins. An Arduino library is available for quick setup via the Library Manager — search for "SparkFun AS7331".
Key Features
- Three UV Channels – UVA, UVB, and UVC with dedicated photodiodes and interference filters
- Four Operating Modes – Single Measurement (CMD), Continuous (CONT), Synchronized Start (SYNS), and Synchronized Start/End (SYND)
- High Dynamic Range – Up to 3.43×10¹⁰ (resolution × gain range)
- Ultra-Low Power – 1.42 mA active, 970 µA standby, 1 µA power-down with automatic power-down between measurements
- Qwiic I²C Interface – 2× Qwiic connectors for solderless assembly, plus through-hole header
- Four I²C Addresses – 0x74 (default), 0x75, 0x76, 0x77 via A0/A1 solder jumpers
- Compact Form Factor – Qwiic Mini footprint at just 1 × 0.5 in.
Specifications
- Sensor – ams OSRAM AS7331
- Operating Voltage – 2.7 V to 3.6 V
- Current (Active) – 1.42 mA typical
- Current (Standby) – 970 µA
- Current (Power Down) – 1 µA
- Interface – I²C (Qwiic compatible)
- Board Size – 1 × 0.5 in.
Ideal For
- UV index monitoring and environmental sensing
- UV sterilisation effectiveness measurement (UVC)
- Wearable sun exposure tracking
- Scientific and industrial UV analysis
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- AS7331
- A sensor chip designed to measure ultraviolet light in separate UVA, UVB and UVC bands. The part number matters because it tells you which libraries, datasheets and measurement capabilities apply to this breakout board.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- dynamic range
- Dynamic range describes how wide a span of values a sensor can measure, from very low to very high. For a light sensor, a wide dynamic range means it can work in dim indoor settings as well as bright sunlight without changing hardware.
- photodiode
- A photodiode is a light-sensitive electronic component that produces a signal when light hits it. In this sensor, multiple photodiodes let the chip measure different parts of the light spectrum separately.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
- Torque
- A twisting force that causes something to rotate, usually measured in newton-metres or kilogram-centimetres. It matters when choosing motors, servos, gears, and tools because higher torque is needed to lift heavier loads, turn larger wheels, or move mechanisms without stalling.
- UVA
- UVA is the longer-wavelength part of ultraviolet light, closest to visible violet light. Measuring it separately matters when you need to distinguish general UV exposure from the more energetic UVB and UVC bands.
- UVB
- UVB is a middle band of ultraviolet light that is more energetic than UVA and is important in sun exposure and plant-related UV monitoring. A sensor with a separate UVB channel lets you measure this band without it being mixed together with other UV light.
- UVC
- UVC is a short-wavelength, high-energy band of ultraviolet light often used in germicidal lamps and curing applications. A separate UVC reading matters if your project needs to monitor or verify UVC sources rather than just detect general UV light.
Find this product in
Sensors & Input
SparkFun Qwiic Mini UV Sensor AS7331 Schematic
Schematic · 101.3 KB · Click any page to view full size
AS7331 Datasheet
Datasheet · 2.2 MB · Click any page to view full size
Supplier page — sparkfun.com
Supplier Description · 671.9 KB · Click any page to view full size
Resources & Downloads
Guides, code examples, and more
Related Tutorials
Free guides on learn.littlebird.com.au
